JP7011938B2 - Loop type heat pipe and its manufacturing method - Google Patents

Description

The present invention relates to a loop type heat pipe and a method for manufacturing the same.

In recent years, mobile devices such as smart phones, tablets, and notebook PCs have been improved in performance and made smaller / thinner, and the amount of heat generated per unit area has been increasing.

Since such a mobile device cannot incorporate a fan for blowing air or a pump for water cooling, it is cooled by using a metal sheet having high thermal conductivity.

However, if the amount of heat generated further increases, sufficient heat dissipation cannot be performed with the metal sheet alone. Therefore, a loop-type heat pipe has been developed in which an evaporator that absorbs heat of heat-generating components and a condenser that dissipates heat are connected in a loop shape with a pipe, and a working fluid is sealed inside.

Japanese Unexamined Patent Publication No. 11-287577 WO2015 / 087451A Japanese Unexamined Patent Publication No. 2016-95108

When housing a loop heat pipe in an electronic device, if it is necessary to change the height position between the evaporator and the condenser, it is necessary to bend the pipe connecting the evaporator and the condenser. ..

The inside of the tube is a small rectangular cavity. Therefore, when the pipe is bent, compressive stress is generated on the inner pipe wall in the bending direction, and the inner pipe wall is pushed and moved inside the pipe. In addition, tensile stress is generated on the outer tube wall of the bend, and the outer tube wall is pulled and moved inside the tube. As a result, the pipe is blocked and does not function as a loop type heat pipe.

It is an object of the present invention to provide a novel structure in which a loop type heat pipe and a method for manufacturing the same do not block the pipe even if the pipe connecting the evaporator and the condenser is bent.

According to one aspect of the following disclosure, the evaporator having a structure in which a plurality of metal layers are laminated and vaporizing the working fluid, the condenser for liquefying the vaporized working fluid, and the evaporator and the condenser A loop type heat pipe having a steam pipe connecting the above and a liquid pipe connecting the evaporator and the condenser, and an outer surface of a first metal layer arranged on the outermost layer of the loop type heat pipe. A first groove portion recessed from the outer surface to the inner surface side is formed, and the first metal layer constitutes a part of the pipe wall of the flow path formed inside the loop type heat pipe. On the inner surface of the first metal layer in contact with the flow path, the surface corresponding to the region where the first groove is formed is parallel to the first groove and does not overlap with the first groove. A loop type heat pipe in which a third groove is formed is provided.

According to the following disclosure, the steam pipe and the liquid pipe of the loop type heat pipe have a bending region to be bent. A groove is formed on the outer surface of each pipe wall inside the bending direction of the steam pipe and the liquid pipe in the bending region in a direction intersecting the bending direction.

Therefore, when the steam pipe and the liquid pipe are bent, the groove portion arranged on the outer surface of the pipe wall inside in the bending direction is pushed by the bending stress to close the opening, and the opposite side walls of the groove portion come into contact with or approach each other to make a cut. Become a department.

As a result, the deformation due to the compressive stress on the inner pipe wall of the bending region is alleviated, and the amount of the inner pipe wall pushed and moved inside the pipe by the bending stress is reduced. Therefore, even if the steam pipe and the liquid pipe are bent, the pipe is not blocked, and a flow path having a sufficient cross-sectional area can be secured.

1 (a) and 1 (b) are a perspective view and a cross-sectional view of a loop type heat pipe used in the study of the inventor of the present application. FIG. 2 is a plan view showing the loop type heat pipe of the first embodiment. 3 (a) is a partial cross-sectional view of the steam pipe of the loop type heat pipe of FIG. 2 along X1-X1, and FIG. 3 (b) is a partial cross-sectional view showing a state in which the steam pipe of FIG. 3 (a) is bent. It is a figure. FIG. 4 is a partial cross-sectional view of the steam pipe of the loop type heat pipe of FIG. 2 along X2-X2. FIG. 5 is a partial cross-sectional view of the liquid pipe of the loop type heat pipe of FIG. 2 along X3-X3. 6 (a) and 6 (b) are a cross-sectional view and a side view (No. 1) showing a method of manufacturing the loop type heat pipe of the first embodiment. 7 (a) and 7 (b) are a cross-sectional view and a side view (No. 2) showing a method of manufacturing the loop type heat pipe of the first embodiment. FIG. 8A is a partial cross-sectional view showing a groove portion of the steam pipe of the loop type heat pipe of the second embodiment, and FIG. 8B is a partial cross-sectional view showing a state in which the steam pipe of FIG. 8A is bent. Is. FIG. 9 is a cross-sectional view showing a method of manufacturing the loop type heat pipe of the second embodiment. 10 (a) is a partial cross-sectional view showing a groove of the steam pipe of the loop type heat pipe of the third embodiment, and FIG. 10 (b) is a partial cross-sectional view showing a state in which the steam pipe of FIG. 10 (a) is bent. Is. FIG. 11 is a cross-sectional view showing a method of manufacturing the loop type heat pipe of the third embodiment. FIG. 12 is a cross-sectional view showing a first application example of the loop type heat pipe of the embodiment. FIG. 13 is a cross-sectional view showing a second application example of the loop type heat pipe of the embodiment. FIG. 14 is a cross-sectional view showing a third application example of the loop type heat pipe of the embodiment.

Hereinafter, embodiments will be described with reference to the accompanying drawings.

Prior to the description of the embodiment, the results of the study conducted by the inventor of the present application will be described.

As shown in FIG. 1 (a), the loop type heat pipe is housed in an electronic device and includes an evaporator 100 and a condenser 200. A steam pipe 300 and a liquid pipe 400 are connected to the evaporator 100 and the condenser 200, whereby a flow path through which a working fluid flows is formed.

The evaporator 100 is fixed on the heat generating component, and the steam of the working fluid is generated by the heat of the heat generating component. The steam is guided to the condenser 200 through the steam pipe 300 and liquefied in the condenser 200. Further, the liquid is returned to the evaporator 100 through the liquid tube 400. In this way, the heat of the heat generating component is transferred to the condenser 200 and dissipated to the outside.

The loop type heat pipe has a coplanar structure because it is manufactured by etching a plurality of flat copper layers and laminating and joining the copper layers.

Therefore, when the evaporator 100 of the loop type heat pipe is fixed on the heat generating component in the electronic device, the evaporator 100 and the condenser 200 are arranged at the same height position.

However, if it is necessary to dissipate heat to the outside by arranging the condenser 200 of the loop type heat pipe in the side plate or the opening of the top plate of the housing of the electronic device, the evaporator 100 and the condenser 200 are connected. It is necessary to bend the steam pipe 300 and the liquid pipe 400.

The flow path inside the steam pipe 300 and the liquid pipe 400 of the loop type heat pipe is a small rectangular cavity in a cross-sectional view. Therefore, as shown in FIG. 1 (b), when the steam pipe 300 and the liquid pipe 400 are bent, compressive stress is generated in the inner pipe wall P1 in the bending direction, and tension is generated in the outer pipe wall P2 in the bending direction. Stress is generated.

As a result, the bent pipe wall P1 and the pipe wall P2 of the steam pipe 300 and the liquid pipe 400 are pushed into the inside of the pipe by bending stress, move and come into contact with each other, so that the steam pipe 300 and the liquid pipe 400 are blocked. It will not function as a loop type heat pipe.

The loop type heat pipe and the method for manufacturing the loop type heat pipe of the embodiment described below can solve the above-mentioned problems.

(First Embodiment)
FIG. 2 is a plan view schematically showing the overall state of the loop type heat pipe of the first embodiment. 3 to 5 are diagrams for explaining the steam pipe and the liquid pipe of the loop type heat pipe of FIG. 2. 6 and 7 are diagrams for explaining the method for manufacturing the loop type heat pipe of the first embodiment.

As shown in FIG. 2, the loop type heat pipe 1 of the embodiment includes an evaporator 10 that vaporizes the working fluid by heat generated by a heat generating component, and a condenser 20 that liquefies the vaporized working fluid. Further, the loop type heat pipe 1 includes a steam pipe 30 for connecting the evaporator 10 and the condenser 20, and a liquid pipe 40 for connecting the evaporator 10 and the condenser 20.

In this way, the steam pipe 30 and the liquid pipe 40 form a loop-shaped flow path through which the working fluid flows. A curved flow path F is arranged in the condenser 20, and the flow path F is connected to the steam pipe 30 and the liquid pipe 40, respectively.

It is fixed to the evaporator 10 of the loop type heat pipe 1 on the heat generating component, and the steam of the working fluid is generated by the heat generated from the heat generating component. The heat generating component is, for example, a semiconductor chip such as a CPU chip.

The heat of vaporization when the working fluid evaporates lowers the temperature of the heat-generating parts. Then, the steam is guided to the condenser 20 through the steam pipe 30, and the heat obtained by the evaporator 10 is dissipated by the condenser 20 to liquefy it.

In this way, the heat generated by the heat generating component is transferred to the condenser 20 and dissipated to the outside. The working fluid liquefied by the condenser 20 is returned to the evaporator 10 through the liquid tube 40. As the working fluid, for example, a fluid having a high vapor pressure such as ammonia, water, chlorofluorocarbon or alcohol is used.

As described above, when it is necessary to dissipate heat to the outside by arranging the condenser 20 of the loop type heat pipe 1 of FIG. 2 in the side plate of the housing of the electronic device or the opening of the top plate, the evaporator 10 It is necessary to bend the steam pipe 30 and the liquid pipe 40 connecting the condenser 20 and the condenser 20.

The loop type heat pipe 1 of FIG. 2 is in a state before being bent, and has a bending region R to be bent later.

Then, as shown in FIG. 2, in the loop type heat pipe 1 of the first embodiment, the steam pipe 30 and the steam pipe 30 in the bending region R are prevented so that the pipes are not blocked when the steam pipe 30 and the liquid pipe 40 are bent. A plurality of first groove portions G1 are formed side by side on each outer surface of the liquid pipe 40. The first groove portion G1 is formed so as to extend linearly in the width direction of the steam pipe 30 and the liquid pipe 40.

FIG. 3A is a partial cross-sectional view of the steam pipe 30 of the loop type heat pipe 1 of FIG. 2 along X1-X1. The inside of the steam pipe 30 is a small rectangular cavity in a cross-sectional view in the width direction. FIG. 3A shows a pipe wall P1 on the upper surface side and a pipe wall P2 on the lower surface side of the steam pipe 30 of FIG.

As shown in FIG. 3A, in the first embodiment, a plurality of first groove portions G1 are formed side by side on the outer surface of the pipe wall P1 inside the bending direction W of the steam pipe 30 in the bending region R. Has been done. The first groove portion G1 is formed so as to extend linearly in a direction intersecting the bending direction W. The direction intersecting the bending direction W is the same as the width direction (FIG. 2) of the steam pipe 30.

Preferably, the first groove portion G1 is arranged in a direction orthogonal to the bending direction W, but the crossing angle may be slightly deviated from the right angle and may intersect the bending direction W.

The thickness T of the pipe wall P1 of the steam pipe 30 is set to, for example, about 0.1 mm, and the depth D of the first groove portion G1 is set to, for example, about 50 μm. Further, the length L of the bending region R in which the plurality of first groove portions G1 are arranged side by side is about 1 mm.

Although not particularly shown, also in the liquid pipe 40 of FIG. 2, a plurality of first groove portions are formed on the outer surface of the pipe wall inside the bending direction in the bending region R, similarly to the steam pipe 30 of FIG. 3 (a). G1s are formed side by side.

The first groove G1 formed in the steam pipe 30 and the liquid pipe 40 is provided to alleviate the deformation of the pipe wall P1 into the pipe due to bending stress when the steam pipe 30 and the liquid pipe 40 are bent. .. The depth, number, arrangement pitch, etc. of the first groove G1 are adjusted according to the bending angle of the steam pipe 30 and the liquid pipe 40.

In this way, the first groove portion G1 is formed on the outer surface of each pipe wall P1 inside the bending direction W of the steam pipe 30 and the liquid pipe 40 in the bending region R in the direction intersecting the bending direction W. There is.

FIG. 4 is a partial cross-sectional view of the steam pipe 30 of the loop type heat pipe 1 of FIG. 2 along X2-X2. As shown in FIG. 4, the steam pipe 30 of the loop type heat pipe 1 of FIG. 2 is formed by laminating six metal layers 51 to 56. By stacking the six metal layers 51 to 56, the evaporator 10, the condenser 20, the steam pipe 30, and the liquid pipe 40 are simultaneously constructed.

The six metal layers 51 to 56 are formed of, for example, a copper layer having excellent thermal conductivity, and are bonded to each other by diffusion bonding.

The first metal layer 51 is formed in the planar shape of the loop type heat pipe 1 of FIG. Further, the second to fifth metal layers 52 to 55 are laminated in a state where openings (52a, 53a, 54a, 55a) are formed.

In the steam pipe 30, the flow path F of the working fluid is constructed by overlapping and communicating the openings 52a to 55a of the metal layers 52 to 55 of the second to fifth layers. The flow path F of the steam pipe 30 is formed in a rectangular shape in a cross-sectional view. For example, the width of the flow path F is about 4 mm, and the height is about 0.4 mm.

Further, the sixth metal layer 56 is formed in the planar shape of the loop type heat pipe 1. The above-mentioned first groove G1 is formed on the upper surface of the sixth metal layer 56.

As described above, the first groove portion G1 is formed on the outer surface of the uppermost sixth metal layer 56. The sixth metal layer 56 arranged on the outermost layer of the loop type heat pipe is an example of the first metal layer.

The uppermost sixth metal layer 56 constitutes a part of the pipe wall of the flow path formed inside the loop type heat pipe 1, and is a first groove portion on the inner surface of the metal layer 56 in contact with the flow path. The surface corresponding to the region where G1 is formed is a smooth surface.

FIG. 5 is a cross-sectional view of the liquid pipe 40 of the loop type heat pipe 1 of FIG. 2 along X3-X3. As shown in FIG. 5, a porous body 42 is constructed in the liquid pipe 40 of the loop type heat pipe 1. The porous body 42 extends to the evaporator 10 along the liquid tube 40, and the working fluid of the liquid phase in the liquid tube 40 is guided to the evaporator 10 by the capillary force generated in the porous body 42.

As shown in FIG. 5, a plurality of holes (52b, 53b, 54b, 55b) penetrating in the thickness direction are formed in the metal layer 52 of the second layer to the metal layer 55 of the fifth layer, respectively. .. These holes 52b to 55b are displaced from each other in a plan view, overlap and communicate with each other, whereby a fine pore flow path of the porous body 42 is constructed.

The pore flow path of the porous body 42 extends three-dimensionally into the porous body 42, and the working fluid permeates three-dimensionally in the pore flow path by the capillary force.

In this way, by adopting a structure that generates a capillary force in the liquid pipe 40 that returns the working liquid to the evaporator 10, even if the electronic device to which the loop type heat pipe 1 is mounted is tilted, the heat is stable. Can be transported.

Further, even if the steam tries to flow back from the evaporator 10 to the liquid tube 40, the steam can be pushed back by the capillary force acting on the working liquid by the porous body 42, and the backflow of the steam can be prevented.

Returning to FIG. 2, the porous body 42 is also provided in the evaporator 10, and the pore flow path of the porous body 42 in the evaporator 10 communicates with the steam pipe 30 and is connected to the porous body 42. ..

As described above, the loop type heat pipe 1 has a structure in which a plurality of metal layers are laminated.

Next, an embodiment in which the steam pipe 30 and the liquid pipe 40 of the loop type heat pipe 1 of FIG. 2 described above are bent will be described.

FIG. 3B shows a state in which the steam pipe 30 of the loop type heat pipe 1 of FIG. 3A is bent in the bending region R. As described above, in the steam pipe 30 before bending in FIG. 3A, a plurality of first groove portions G1 are formed on the outer surface of the pipe wall P1 of the steam pipe 30 inside the bending direction W.

Therefore, as shown in FIG. 3 (b), when the steam pipe 30 of FIG. 3 (a) is bent in the bending direction W, a plurality of firsts arranged on the outer surface of the pipe wall P1 inside the bending direction W. The groove portion G1 of the first groove portion G1 is pushed by the bending stress to close the opening, and the facing side walls of the first groove portion G1 are in contact with or close to each other.

At this time, the bent steam pipe 30 is in a state in which the cut portion C1 in which the first groove portion G1 is closed is arranged on the outer surface of the pipe wall P1 inside the bending region R. The cut portion C1 is formed by contacting or approaching the facing side walls of the first groove portion G1.

In the example of FIG. 3B, the cut portion C1 is formed so that the vertices (open ends) of the first groove portion G1 come into contact with each other and a cavity is left inside.

As a result, the deformation inside the pipe due to the compressive stress at the pipe wall P1 inside the bending region R of the steam pipe 30 is alleviated, and the pipe wall P1 of the steam pipe 30 is pushed and moved inside the pipe by the bending stress. The amount decreases. Therefore, even if the steam pipe 30 is bent, the steam pipe 30 is not blocked, and a flow path having a sufficient cross-sectional area can be secured.

Further, even if the steam pipe 30 is bent, the inner surface of the steam pipe 30 in the bending region R has a smooth curved surface without unevenness, so that the fluid resistance of the working liquid in the flow path does not increase.

When the steam pipe 30 is bent, the liquid pipe 40 is also bent at the same time. Since the same first groove G1 is formed in the liquid pipe 40, it is possible to secure a flow path having a sufficient cross-sectional area without blocking the liquid pipe 40.

Next, a method for manufacturing the loop type heat pipe of the first embodiment will be described.

First, a plurality of metal layers are prepared. Preferably, as shown in FIG. 6A, six metal layers 51 to 56 from the first layer to the sixth layer are prepared.

As the metal layers 51 to 56, for example, a copper layer having a thickness of about 0.1 mm is used. The lowermost first layer metal layer 51 and the uppermost sixth layer metal layer 56 are formed in the planar shape of the loop type heat pipe 1 of FIG. 2 described above.

Openings (52a, 53a, 54a, 55a) are formed in the metal layers 52 to 55 of the second to fifth layers. The openings 52a to 55a of the metal layers 52 to 55 are formed corresponding to the evaporation portion 10, the condenser 20, the steam pipe 30, and the liquid pipe 40 of the loop type heat pipe 1 described above.

Further, as described with reference to FIG. 5 described above, holes (52b, 53b) for constructing the porous body 42 are formed in the metal layers 52 to 55 of the second to fifth layers of the portion corresponding to the liquid pipe 40. , 54b, 55b) are formed, respectively.

Further, on the upper surface of the sixth metal layer 56, the first groove portion G1 of the steam pipe 30 and the liquid pipe 40 of FIGS. 2 and 3A described above is previously formed. In this way, the first groove portion G1 is formed on the upper surface of the uppermost metal layer 56 corresponding to the bending region R in the direction intersecting the bending direction W.

Among the plurality of metal layers, the first groove portion G1 is formed on the outer surface of the metal layer arranged on the outermost surface in the step of laminating the plurality of metal layers.

The first metal layer 51 and the sixth metal layer 56 are formed by patterning the metal layers so as to have the planar shape of the loop type heat pipe 1 of FIG.

Further, the metal layers are also patterned and formed in the openings 52a to 55a and the holes 52b to 55b (FIG. 5) of the metal layers 52 to 55 of the second to fifth layers.

A resist pattern layer is formed on the metal layer by photolithography, and the metal layer is penetrated by wet etching using the resist pattern layer as a mask. Wet etching may be performed from both sides of the metal layer for penetration processing.

Further, the first groove portion G1 on the upper surface of the uppermost metal layer 56 is formed by wet etching from the upper surface of the metal layer to the middle of the thickness using the resist pattern layer as a mask.

When the metal layers 51 to 56 are copper layers, a cupric chloride aqueous solution, a ferric chloride aqueous solution, or the like is used as the etching solution.

Alternatively, the first groove portion G1 may be formed by laser machining the upper surface of the uppermost metal layer 56. As the laser, for example, a carbon dioxide (CO ₂ ) laser is used.

Then, by laminating the above-mentioned first to sixth metal layers 51 to 56 and pressing while heating at a temperature of 900 ° C., diffusion bonding is performed by utilizing the diffusion of atoms generated on the bonding surface. The metal layers 51 to 56 are joined to each other.

As a result, the evaporator 10 and the condenser 20 of FIG. 2 described above, the steam pipe 30 connecting the evaporator 10 and the condenser 20, and the liquid pipe 40 connecting the evaporator 10 and the condenser 20 are formed.

As a result, as shown in FIG. 6B, the loop type heat pipe 1 having the same planar structure is manufactured. The loop type heat pipe 1 of FIG. 6B corresponds to a side view of the loop type heat pipe 1 in the plan view of FIG. 2 described above as viewed from the lateral direction on the steam pipe 30 side.

Next, as shown in FIG. 7A, a pressing member 60 and a punch 62 are prepared as a mold. Then, the loop type heat pipe 1 of FIG. 6B is turned upside down, and the loop type heat is placed on the pressing member 60 with the surface on which the first groove portion G1 (not shown) is formed facing downward. Place the pipe 1.

At this time, the bending region R in which the steam pipe 30 of the loop type heat pipe 1 and the first groove portion G1 of the liquid pipe 40 are arranged is arranged at the end of the pressing member 60.

Further, the punch 62 presses the loop type heat pipe 1 in the region protruding from the pressing member 60 downward, and bends the loop type heat pipe 1 in the bending region R of the steam pipe 30 and the liquid pipe 40.

As a result, as shown in FIG. 7B, the loop type heat pipe 1 is bent in the bending region R. At this time, as shown in FIG. 3B described above, the steam pipe 30 and the liquid pipe 40 of the loop type heat pipe 1 are bent without being blocked.

Further, as shown in the partially enlarged view of FIG. 7 (b), as in FIG. 3 (b) described above, the first groove portion arranged on the outer surface of the pipe wall P1 of the steam pipe 30 inside the bending direction W. G1 is closed by bending to become a notch C1.

In this way, in the region where the first groove portion G1 is formed, the first groove portion G1 is bent inward and the bending line direction is substantially parallel to the first groove portion G1. The bending line direction is the direction of the bending line generated on the outer surface when the steam pipe 30 and the liquid pipe 40 are bent, and is the same direction as the width direction of the steam pipe 30 and the liquid pipe 40.

Alternatively, although not particularly shown, the mold is provided with a lower mold in which a V-shaped recess having a predetermined angle is formed on the upper surface in a cross-sectional view, and a V-shaped protrusion that fits into the V-shaped recess of the lower mold. You may use the upper mold.

In this case, the loop type heat pipe 1 is arranged between the lower mold and the upper mold with the first groove G1 facing upward, and the lower mold is pressed by the upper mold to press the steam pipe 30 and the liquid pipe 40. Is bent corresponding to the V-shaped recess.

When changing the height position with the evaporator 10 and the condenser 20 arranged in the horizontal direction, a mold for bending the steam pipe 30 and the liquid pipe 40 of the loop type heat pipe 1 is used. Will be done.

By press working using a die, the steam pipe 30 and the liquid pipe 40 can be bent so that the evaporator 10 and the condenser 20 of the loop type heat pipe 1 are arranged at required positions.

(Second Embodiment)
FIG. 8 is a diagram for explaining the state of a groove formed in the steam pipe of the loop type heat pipe of the second embodiment, and FIG. 9 is a diagram for explaining a method of manufacturing the loop type heat pipe of the second embodiment. Is.

In the second embodiment, detailed description of the same elements and the same steps of the manufacturing method as in the first embodiment will be omitted.

In the loop type heat pipe of the second embodiment, as shown in FIG. 8A, in the steam pipe 30 of FIG. 3A of the first embodiment, the pipe wall P2 outside the bending direction W of the steam pipe 30 A plurality of second groove portions G2 extending linearly in a direction intersecting the bending direction W are also formed side by side on the outer surface of the above. Further, in the liquid pipe 40 of the loop type heat pipe 1 of FIG. 2, the second groove portion G2 is additionally formed in the same manner.

The first groove portion G1 and the second groove portion G2 are formed so as to cross each width direction of the steam pipe 30 and the liquid pipe 40.

As described above, in the second embodiment, the second groove portion on the outer surface of each pipe wall P2 outside the bending direction W of the steam pipe 30 and the liquid pipe 40 in the bending region R in the direction intersecting the bending direction W. G2 is additionally formed.

On the outer surface of the lowermost metal layer 51 in FIG. 4 described above, the second groove portion G2 is formed at a position overlapping the region where the first groove portion G1 is formed. This is an example of a second metal layer in which the lowermost metal layer 51 in FIG. 4 is arranged on the outermost layer on the opposite side of the first metal layer.

The lowermost metal layer 51 in FIG. 4 constitutes a part of the pipe wall of the flow path formed inside the loop type heat pipe, and the second groove portion G2 is formed on the inner surface of the metal layer 51 in contact with the flow path. The surface corresponding to the region where is formed is a smooth surface.

Therefore, as shown in FIG. 8B, when the steam pipe 30 of FIG. 8A is bent in the bending direction W, the pipe inside the bending direction W of the steam pipe 30 is similarly formed in the first embodiment. A plurality of first groove portions G1 arranged on the outer surface of the wall P1 are closed. Then, the facing side walls of the first groove portion G1 come into contact with or approach each other to form the cut portion C1.

At the same time, a plurality of second groove portions G2 arranged on the outer surface of the pipe wall P2 outside the bending direction W of the steam pipe 30 are opened, and extend in the width direction of the second groove portion G2 and expand to the first recess. It becomes H1. The width of the first recess H1 is wider than the width of the second groove G2, and the depth of the first recess H1 is shallower than the depth of the second groove G2.

As a result, the compressive stress on the inner pipe wall P1 in the bending direction W of the steam pipe 30 is relaxed, and the amount of the inner pipe wall P1 in the bending direction of the steam pipe 30 being pushed and moved inside the pipe by the bending stress. Decrease.

In other words, the pipe wall P2 on the outer side in the bending direction can be deformed in the tensile direction with less stress than in the case where the second groove portion G2 is not formed, and thus the pipe wall P1 on the inner side in the bending is applied accordingly. The stress is reduced and the deformation of the pipe wall P1 is alleviated.

Further, in the second embodiment, the deformation inside the pipe due to the tensile stress at the pipe wall P2 outside the bending direction W of the steam pipe 30 is alleviated, and the pipe wall P2 outside the bending direction W of the steam pipe 30 is the pipe. The amount of movement that is pushed inside by bending stress is reduced.

As a result, even if the steam pipe 30 is bent, the steam pipe 30 is not blocked, and a flow path having a sufficient cross-sectional area can be secured.

Further, even if the steam pipe 30 is bent, the inner surface of the steam pipe 30 in the bending region R has a smooth curved surface without unevenness, so that the fluid resistance of the working fluid in the flow path does not increase.

When the steam pipe 30 is bent, the liquid pipe 40 is also bent at the same time. Since the same first groove portion G1 and second groove portion G2 are formed in the liquid pipe 40, it is possible to secure a flow path having a sufficient cross-sectional area without blocking the liquid pipe 40.

In the second embodiment, since the amount of the steam pipe 30 and the liquid pipe 40 pushed and moved into the pipe inside the pipes P1 and P2 both inside and outside in the bending direction by the bending stress is reduced, so that the first embodiment is performed. It is possible to secure a larger cross-sectional area of the flow path in the bending region R than that.

Next, a method for manufacturing the loop type heat pipe of the second embodiment will be described. As shown in FIG. 9, in FIG. 6A of the manufacturing method of the first embodiment described above, the metal layer 51 of the first layer is arranged on the outer surface of the pipe wall P2 of FIG. 8A described above on the lower surface of the metal layer 51. The second groove G2 formed is additionally formed.

In this way, a second groove portion G2 is additionally formed on the lower surface of the lowermost metal layer 51 corresponding to the bending region R in the direction intersecting the bending direction W.

In this state, the metal layers 51 to 56 of the first layer to the sixth layer are laminated and joined, and the same steps as those in FIGS. 7 (a) and 7 (b) described above are carried out to perform the second embodiment. Loop type heat pipe is manufactured.

(Third Embodiment)
FIG. 10 is a diagram for explaining an aspect of a groove formed in the steam pipe of the loop type heat pipe of the third embodiment, and FIG. 11 is a diagram for explaining a method of manufacturing the loop type heat pipe of the third embodiment. Is. In the third embodiment, detailed description of the same elements as those of the first and second embodiments and the same steps of the manufacturing method will be omitted.

As shown in FIG. 10A, in the loop type heat pipe of the third embodiment, in the steam pipe 30 of FIG. 8A of the second embodiment described above, the pipe inside the bending direction W of the steam pipe 30. A plurality of third groove portions G3 extending linearly in a direction intersecting the bending direction W are additionally formed on the inner surface of the wall P1.

The third groove portion G3 on the inner surface of the pipe wall P1 of the steam pipe 30 is arranged in a portion corresponding to the region between the plurality of first groove portions G1 on the outer surface of the pipe wall P1, and the first groove portion G1 and the third groove portion G1 are arranged. The groove portions G3 of the above are arranged alternately.

By arranging the first groove portions G1 and the third groove portions G3 in a staggered manner, it is possible to secure the remaining thickness of the pipe wall P substantially thicker than in the case where the first groove portions G1 and the third groove portions G3 are arranged at the same corresponding positions. Therefore, it is possible to secure a certain strength after bending the steam pipe 30.

As described above, on the inner surface of the uppermost metal layer 56 (first metal layer) in contact with the flow path of FIG. 4 described above, the first groove portion G1 is formed on the surface corresponding to the region where the first groove portion G1 is formed. A third groove G3 is formed at a position parallel to and not overlapping with the first groove G1. Further, as shown in FIG. 10 (a), the steam of FIG. 8 (a) of the above-mentioned second embodiment is formed. In the pipe 30, a plurality of fourth groove portions G4 extending linearly in a direction intersecting the bending direction are additionally formed on the inner surface of the pipe wall P2 outside the bending direction W of the steam pipe 30.

Also in the pipe wall P2 of the steam pipe 30, the second groove portion G2 on the outer surface and the fourth groove portion G4 on the inner surface are arranged so as to be staggered.

Further, in the liquid pipe 40 of the loop type heat pipe 1 of FIG. 2, similarly, the third groove portion G3 and the fourth groove portion G4 are additionally formed.

As described above, in the third embodiment, the third groove portion on the inner surface of each pipe wall P1 inside the bending direction W of the steam pipe 30 and the liquid pipe 40 in the bending region R in the direction intersecting the bending direction W. G3 is additionally formed.

Further, a fourth groove G4 is additionally formed on the inner surface of each pipe wall P2 outside the bending direction W of the steam pipe 30 and the liquid pipe 40 in the bending region R in a direction intersecting the bending direction.

On the inner surface of the lowermost metal layer 51 (second metal layer) in contact with the flow path of FIG. 4 described above, the surface corresponding to the region where the second groove portion G2 is formed is parallel to the second groove portion G1. Moreover, a fourth groove portion G4 that does not overlap with the second groove portion G2 is formed.

Therefore, as shown in FIG. 10 (b), when the steam pipe 30 of FIG. 10 (a) is bent in the bending direction W, the pipe inside the bending direction W of the steam pipe 30 is similarly formed in the first embodiment. A plurality of first groove portions G1 arranged on the outer surface of the wall P1 are closed to form a notch portion C1.

At the same time, a plurality of third groove portions G3 arranged on the inner surface of the pipe wall P1 inside the bending direction W of the steam pipe 30 extend and expand in the width direction to become the second recess H2.

As a result, the deformation of the steam pipe 30 in the pipe wall P1 inside the bending direction W is alleviated. Therefore, the amount of the pipe wall P1 inside the bending direction W of the steam pipe 30 pushed and moved into the pipe by the bending stress is further reduced as compared with the first and second embodiments.

Further, as also shown in FIG. 10 (b), when the steam pipe 30 of FIG. 10 (a) is bent in the bending direction W, the pipe outside the bending direction W of the steam pipe 30 is similarly formed in the second embodiment. A plurality of second groove portions G2 arranged on the outer surface of the wall P2 expand in the width direction to become the first recess H1.

Further, in the third embodiment, the plurality of fourth groove portions G4 arranged on the inner surface of the pipe wall P2 outside the bending direction W of the steam pipe 30 expand in the width direction to become the third recess H3. , The steam pipe 30 is easily deformed in the pulling direction on the pipe wall P2 outside the bending direction W. Therefore, the amount of the pipe wall P2 outside the bending direction of the steam pipe 30 pushed and moved into the pipe by the bending stress is further reduced as compared with the first and second embodiments.

When the steam pipe 30 is bent, the liquid pipe 40 is also bent at the same time. Since the same first to fourth groove portions G1, G2, G3, and G4 are formed in the liquid pipe 40 as well, it is necessary to secure a flow path having a sufficient cross-sectional area without blocking the liquid pipe 40. Can be done.

As described above, in the third embodiment, the first groove portion G1 and the third groove portion G3 are formed on the outer surface and the inner surface of the pipe wall P1 inside the bending direction W of the steam pipe 30, respectively. Further, a second groove portion G2 and a fourth groove portion G4 are formed on the outer surface and the inner surface of the pipe wall P2 on the outer side in the bending direction W, respectively. Then, similar first to fourth groove portions G1 to G4) are formed on the pipe wall of the bending region R of the liquid pipe 40.

As a result, when the steam pipe 30 and the liquid pipe 40 are bent, the pipe walls P1 and P2 both inside and outside the bending direction of the steam pipe 30 and the liquid pipe 40 are pushed into the pipe by bending stress. The amount of movement is reduced.

Therefore, it is possible to secure a larger cross-sectional area of the flow path in the bending region R of the steam pipe 30 and the liquid pipe 40 than in the first and second embodiments.

In the third embodiment, as shown in FIG. 10B, when the steam pipe 30 is bent, the width of the third groove G3 is widened on the inner surface of the pipe wall P1 of the steam pipe 30. The inner surface of the pipe wall P1 in the bending region R becomes an uneven curved surface.

Further, also on the inner surface of the pipe wall P2 of the bending region R, the third concave portion H3 remains, so that the curved surface has an uneven shape.

Therefore, the fluid resistance of the working fluid in the bending region R of the steam pipe 30 is slightly higher than that in the first and second embodiments.

However, in the present embodiment, the second concave portion H2 is formed in the thickness direction from the inner surface of the pipe wall P1 of the steam pipe 30 to form an uneven shape. Further, also in the pipe wall P2 of the steam pipe 30, a third concave portion 3 is formed in the thickness direction from the inner surface to form a concave shape.

Therefore, the barrier of the working fluid is smoother than that of the structure forming the protrusion protruding inward from the inner surface of the pipe wall, so that the increase in fluid resistance is small.

Next, a method for manufacturing the loop type heat pipe according to the third embodiment will be described. As shown in FIG. 11, in FIG. 9 of the manufacturing method of the second embodiment described above, on the lower surface of the metal layer 56 of the sixth layer, on the inner surface of the pipe wall P1 inside the bending direction W of FIG. 10 (a). A third groove G3 to be arranged is additionally formed.

Further, in FIG. 9 described above, a fourth groove portion G4 arranged on the inner surface of the outer pipe wall P2 in the bending direction of FIG. 10 is additionally formed on the upper surface of the metal layer 51 of the first layer.

In this way, a third groove portion G3 is additionally formed on the lower surface of the uppermost metal layer 56 corresponding to the bending region R in the direction intersecting the bending direction W.

Further, a fourth groove portion G4 is additionally formed on the upper surface of the lowermost metal layer 51 corresponding to the bending region R in the direction intersecting the bending direction W.

Since the third groove G3 on the inner surface of the metal layer 56 and the fourth groove G4 on the inner surface of the metal layer 51 of FIG. 11 are formed only inside the joints of the metal layers 51 to 56, the inside of the pipe is formed. The sealing property of the flowing working fluid is maintained, and no liquid leakage occurs.

In this state, the metal layers 51 to 56 of the first layer to the sixth layer are laminated and joined, and the same steps as those in FIGS. 7 (a) and 7 (b) described above are performed to carry out the third embodiment. Loop type heat pipe is manufactured.

(Application example of the loop type heat pipe of the embodiment)
Next, an example of applying a bent loop type heat pipe to an electronic device will be described. FIG. 12 shows a first application example of the loop type heat pipe of the embodiment. As shown in FIG. 12, a semiconductor chip 70, which is an example of heat-generating components, is mounted on a substrate 5 of an electronic device.

Further, the electronic component 72 is mounted on the lateral substrate 5 of the semiconductor chip 70. The height of the electronic component 72 is higher than the height of the semiconductor chip 70.

Therefore, in order to fix the evaporator 10 of the loop type heat pipe 1 on the semiconductor chip 70 and arrange the condenser 20 horizontally on the electronic component 72 side without tilting the condenser 20, the steam pipe 30 and the liquid pipe 40 are placed on the upper side. Needs to be bent.

In the first application example, the steam pipe 30 and the liquid pipe 40 are bent at two places in order to change the height position while the evaporator 10 and the condenser 20 are arranged in the horizontal direction.

Then, the heat generated from the semiconductor chip 70 is dissipated from the condenser 20 to the outside through the evaporator 10 and the steam tube 30.

In the loop type heat pipe 1 of the present embodiment, since the porous body 42 is arranged in the liquid pipe 40 and the evaporator 10, even if the height position is different between the evaporator 10 and the condenser 20, the capillary tube is used. The working fluid can be stably transported by force.

FIG. 13 shows a second application example of the loop type heat pipe of the embodiment. As shown in FIG. 13, in the second application example, the condenser 20 is arranged next to the opening 6x of the side plate 6a of the housing 6 of the electronic device.

Therefore, the steam pipe 30 and the liquid pipe 40 of the loop type heat pipe 1 are bent in the vertical direction, and the condenser 20 is arranged upright in the vertical direction. Then, the evaporator 10 of the loop type heat pipe 1 is fixed on the semiconductor chip 70, and the condenser 20 is arranged near the inside of the opening 6x of the side plate 6a of the housing 6.

In the second application example, the heat generated from the semiconductor chip 70 is transferred to the condenser 20 through the evaporator 10 and the steam tube 30, and is dissipated to the outside from the opening 6x of the side plate 6a of the housing 6.

FIG. 14 shows a third application example of the loop type heat pipe of the embodiment. As shown in FIG. 14, in the third application example, the condenser 20 is arranged under the opening 6x of the top plate 6b of the housing 6 of the electronic device.

Therefore, the steam pipe 30 and the liquid pipe 40 of the loop type heat pipe 1 are bent into a horizontal U shape, and the condenser 20 is arranged on the upper side of the evaporator 10 at a predetermined interval. Then, the evaporator 10 of the loop type heat pipe is fixed on the semiconductor chip 70, and the condenser 20 is arranged near the lower side of the opening 6x of the top plate 6b of the housing 6.

In the third application example, the heat generated from the semiconductor chip 70 is transferred to the condenser 20 through the evaporator 10 and the steam tube 30, and is dissipated to the outside from the opening 6x of the top plate 6b of the housing 6.

In the present embodiment, as described above, even if the steam pipe 30 and the liquid pipe 40 of the loop type heat pipe 1 are bent, the steam pipe 30 and the liquid pipe 40 are not blocked. Therefore, since the evaporator 10 and the condenser 20 of the loop type heat pipe 1 can be arranged at different height positions in the electronic device, the degree of freedom in designing the electronic device can be increased.

Further, in the loop type heat pipe 1 of the present embodiment, a groove portion for bending is formed in the steam pipe 30 and the liquid pipe 40, but when it is not necessary to perform bending, it is used in a state of the same plane structure. You may.

1 ... loop type heat pipe, 5 ... substrate, 6 ... housing, 6a ... side plate, 6b ... top plate, 6x, 51a-56a ... opening, 10 ... evaporator, 20 ... condenser, 30 ... steam tube, 40 Liquid tube, 42 ... porous body, 51-56 ... metal layer, 51b-56b ... hole, 60 ... presser member, 62 ... punch, 70 ... semiconductor chip, 72 ... electronic component, C1 ... notch, F ... Flow path, G1 ... 1st groove, G2 ... 2nd groove, G3 ... 3rd groove, G4 ... 4th groove, H1 ... 1st recess, H2 ... 2nd recess, H3 ... 3rd Recess, R ... Bending area, P1, P2 ... Pipe wall, W ... Bending direction.

Claims (7)

It consists of a structure in which multiple metal layers are laminated.
An evaporator that vaporizes the working fluid and
The condenser that liquefies the vaporized working fluid and
A steam tube connecting the evaporator and the condenser,
A loop type heat pipe having a liquid pipe connecting the evaporator and the condenser.
On the outer surface of the first metal layer arranged in the outermost layer of the loop type heat pipe, a first groove portion recessed from the outer surface to the inner surface side is formed.
The first metal layer constitutes a part of the pipe wall of the flow path formed inside the loop type heat pipe.
On the inner surface of the first metal layer in contact with the flow path, the surface corresponding to the region where the first groove is formed is parallel to the first groove and does not overlap with the first groove. A loop type heat pipe characterized in that a third groove is formed in the heat pipe. On the outer surface of the second metal layer arranged on the outermost layer on the opposite side of the first metal layer, the second groove is formed at a position overlapping the region where the first groove is formed. The loop type heat pipe according to claim 1. The second metal layer constitutes a part of the pipe wall of the flow path formed inside the loop type heat pipe.
On the inner surface of the second metal layer in contact with the flow path, the surface corresponding to the region where the second groove is formed is parallel to the second groove and does not overlap with the second groove. The loop type heat pipe according to claim 2, wherein the groove portion is formed. The loop type heat pipe according to any one of claims 1 to 3 , wherein the first groove portion is formed in the steam pipe or the liquid pipe. The claim is characterized in that, in the region where the first groove portion is formed, the first groove portion is inside and the bending line direction is bent so as to be parallel to the first groove portion. Item 6. The loop type heat pipe according to any one of Items 1 to 4 . It is a manufacturing method of loop type heat pipe.
The process of preparing multiple metal layers and
A step of forming an evaporator, a condenser, a steam tube connecting the evaporator and the condenser, and a liquid tube connecting the evaporator and the condenser by laminating the plurality of metal layers. ,
A step of forming a first groove portion recessed from the outer surface to the inner surface side on the outer surface of the first metal layer arranged on the outermost surface of the plurality of laminated metal layers.
On the inner surface of the first metal layer, the third groove portion is located on the surface corresponding to the region where the first groove portion is formed, at a position parallel to the first groove portion and not overlapping with the first groove portion. With the process of forming,
The first metal layer constitutes a part of the pipe wall of the flow path formed inside the loop type heat pipe, and the inner surface of the first metal layer is in contact with the flow path. How to make a type heat pipe. A claim comprising a step of bending so that the first groove portion is inside and the bending line direction is parallel to the first groove portion in the region where the first groove portion is formed. Item 6. The method for manufacturing a loop type heat pipe according to Item 6.

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